In communication networks, it is generally desirable to prevent service outages and/or loss of network traffic. By way of example, such service outages and/or loss of network traffic may occur when a network device fails, loses power, is taken offline, is rebooted, a communication link to the network device breaks, etc.
In order to prevent such service outages and/or loss of network traffic, the communication networks may utilize inter-chassis redundancy (ICR). In an ICR system, there are typically two ICR devices (i.e., nodes). There may, however, be more than two ICR devices in an ICR system. During normal operation, one ICR device is configured to be in active state while the other is configured to be in standby state. The active ICR device is responsible for handling network traffic with a plurality other network devices (e.g., end stations), including, for example, allocating Internet Protocol (IP) addresses to such end stations. During a switchover, the active and standby ICR devices switch roles, e.g., the active ICR device becomes the standby ICR device, and the standby ICR device becomes the active ICR device.
Each active ICR device maintains session records and ICR related resources (which shall herein be simply referred to as session records) that are required for handling network traffic with the end stations. In order for a standby ICR device to seamlessly handle network connections with the end stations after a switchover event, the session records must be synced from the active to standby ICR device. Conventionally, when an ICR device initially comes up as a standby ICR device, a bulk sync process is performed. As used herein, a bulk sync refers to the transmitting (i.e., copying) of all session records from the active ICR device to the standby device when the standby ICR device initially becomes part of the ICR system.
During the bulk sync process, there may be one or more switchover events that require a standby ICR device to become the active ICR device and commence handling of network traffic with the end stations. This is problematic because the standby ICR device may not have received all the most up to date session records due to the fact that the bulk sync process had been interrupted by the switchover event.
In some instances, multiple ICR devices may be configured as active ICR devices. This is known as a split-brain configuration. In such a scenario, each active ICR device maintains session records with the end station(s) that it has a network connection with. These session records, however, do not exist on the peer active ICR device. When the split-brain scenario is resolved, only one ICR device remains as the active ICR device. Conventionally, a standby ICR device does not sync/transmit session records to an active ICR device. This is problematic because the sole active ICR device does not have the session records needed to manage the network connections that were previously managed by the peer active ICR devices during the split-brain scenario.